Testing the isomorph invariance of the bridge functions of Yukawa one-component plasmas. II. Short range

TL;DR

This study confirms that Yukawa bridge functions are nearly invariant along isomorphs even at short ranges, supporting the broader invariance hypothesis for R-simple liquids.

Contribution

It introduces a new methodology for computing short-range Yukawa bridge functions using cavity distribution and extrapolation techniques.

Findings

Yukawa bridge functions are nearly invariant along isomorphs at short range.

A novel approach for calculating short-range bridge functions is developed.

Quantification of errors in the computation process is provided.

Abstract

It has been conjectured that bridge functions remain nearly invariant along phase diagram lines of constant excess entropy for the class of R-simple liquids. In the companion paper, this hypothesis has been confirmed for Yukawa bridge functions outside the correlation void. In order to complete the testing of the invariance ansatz, Yukawa bridge functions are here computed inside the correlation void with the cavity distribution method and input from ultra-long molecular dynamics simulations featuring a tagged particle pair. A general methodology is developed for the design of the tagged pair interaction potential that leads to the acquisition of uniform statistics. An extrapolation technique is developed to determine the bridge function value at zero separation. The effect of different sources of errors is quantified. Yukawa bridge functions are demonstrated to be nearly isomorph invariant also in the short range. Generalization to all R-simple systems and practical implications are discussed.